Determination of geographic position of an object, equipment or a person carrying the equipment has become more and more interesting in many fields of application, particularly true within the field of wireless communication. Positioning systems and methods are increasing recent years. LoCation Service (LCS) and related protocols have been standardized by 2G mobile network protocols. By making use of the radio signal measurements, possibility to determine and report the (geographic) location of the mobile station (MS) also can be found in 3GPP standards, such as 3GPP TS 22.071, TS 23.271, TS 43.059, TS 49.031, TS 48.071 and TS 44.031.
Global Navigation Satellite System (GNSS) is a satellite system for positioning purposes. Systems belonging to this category, that are operational today or will be in the near future are, for example, Global Positioning System (GPS), Galileo, Satellite Based Augmentation Systems (SBAS), Modernized GPS, Quasi Zenith Satellite System (QZSS), GLONASS, etc. . . . .
A terminal with GNSS measurement capability may operate in an autonomous mode or in an assisted mode. In the autonomous mode, a terminal determines its position based on signals received from GNSS without assistance from network. For example, a Cell ID based positioning solution, which requires no assistance data, can be used by a terminal in the autonomous mode.
In the assisted mode, for example, a MS-assisted mode or a MS-based mode, a terminal receives assistance data from network. In the MS-assisted mode, a terminal provides position measurements to the network for computation of a location estimate by the network and the network may provide assistance data to the terminal to enable position measurements and/or improve measurement performance. While in the MS-based mode, a terminal performs both position measurements and computation of a location estimate and the network provides to the terminal assistance data useful or essential to one or both of these functions. Generally, a terminal in the MS-based mode needs more assistance data than one in the MS-assisted mode. In other words, a MS-based positioning solution requires more assistance data than a MS-based positioning solution.
It can be seen that, in the currently wireless positioning communication system, there are complicated scenarios and many different position solutions to be applied in those scenarios. If a position solution is improperly applied in a concrete scenario, the possibility of positioning failure will be highly increased and the positioning accuracy will be reduced. Therefore, how to select a position solution which is suitable for a concrete scenario is an important problem.